85 



and bottom are sprinkled with milk of lime at 10 or 

 12 B. 



This attention to cleanliness, which is easily 

 done at any rale, is of the highest importance to the 

 regular working of the manufacture. 



The syrups evaporated, that is to say brought to 

 $5 or 27 u B first pass to a nr-w filter, and the simple 

 juice succeeds to the syrups. 



EVAPORATING APPARATUS. 



This apparatus called a triple effe 1 , is very difficult 

 to explain without the machine itself in view. I 

 will try however to give to my readers as exact 

 an idea as possible. It is composed of three principal 

 parts ; three boilers or chores, the safety columns, 

 the condenser and air pump. 



Before explaining the apparatus I will first ex- 

 plain the principle upon which it is based ; the rest 

 will be more easily understood. 



It is known that the air presses upon the surface 

 of the earth and upon every thing thereon. The 

 barometer shews the measure of this pressure. 



We know that under atmospheric pressure (30 

 inches) water begins to boil a 212" Fahr. Juice boils 

 at a temperature a little higher which increases as 

 the concentration advances. To arrive at a suffi- 

 cient concentration, the syrup should remain a con- 

 siderable time under this high temperature, which 

 is not without serious inconveniences for the sugar. 



It has been noticed that if we could work in a 



